John is a cash-basis taxpayer. He received the following items of income in December 2018: 1. The loan on his truck was forgiven because he performed accounting work for the dealer. He owed $2,000 at the time. 2. He received a retainer of $500 from a new client to guarantee that his services would be available in February when the client would need help preparing financial statements. 3. He finally received the $800 for work he completed in November of 2017. How much of this income must John include on his 2018 tax return